The skin acts as the body""s first line of defense against infection. Accordingly, it is important that lesions or wounds in the skin must be rapidly closed to prevent infection. Some types of wounds, however, are resistant to healing under normal physiological conditions. For example, chronic ulcers may be defined as wounds that fail to heal. Such ulcers are a common complication of diseases such as diabetes or other pathologies where chronic venous insufficiency occurs. Methods of healing such ulcers have received significant attention recently. See, for example, U.S. Pat. No. 5,693,332 (use of keratinocytes), U.S. Pat. No. 5,646,117 (use of monocyte chemotactic and activating factor, MCAF), U.S. Pat. No. 5,202,118 (use of IL-1), and U.S. Pat. No. 5,599,788 (use of H3 protein), the respective disclosures of which are hereby incorporated by reference in their entireties.
It is apparent, therefore, that improved methods for treating chronic wounds, such as chronic ulcers, are greatly to be desired. In particular, new methods are needed for accelerating healing of chronic wounds.
Previous work has shown that protease activity is increased in chronic wounds. See Palolahti et al., Exp. Derm., 2:29 (1993) and Wysocki et al., J. Invest. Dermatol. 101:64 (1993). The present inventors have found that inhibition of this protease activity may be used to treat such chronic wounds.
It is therefore an object of the present invention to provide improved methods for treating wounds.
It is a further object of the present invention to provide pharmaceutical compositions for use in methods of wound healing.
In accomplishing these objects, there has been provided, in accordance with one aspect of the present invention, a method of treating wounds, comprising administering to a patient in need thereof an effective amount of a therapeutic agent comprising a serine protease inhibitor, where the serine protease inhibitor is topically administered to a wound. In one embodiment, the therapeutic agent comprises a urokinase inhibitor. In another embodiment, the therapeutic agent is selected from the group consisting of plasminogen activator inhibitor 2 (PAI-2), a variant thereof having plasminogen activating inhibitory properties, a derivative of PAI-2, and a variant of a derivative of PAI-2. In still another embodiment, the serine protease inhibitor is administered in a gel formulation. The gel may be a cellulose gel further comprising a detergent. The detergent may be Tween-80.
In accordance with another aspect of the invention there has been provided a method of treating wounds comprising administering to a patient in need thereof an effective amount of a therapeutic agent comprising PAI-2, a variant, derivative, or variant of a derivative of PAI-2, and at least one other serine protease inhibitor, where the therapeutic agent is topically administered to the wound. In one embodiment, the other serine protease inhibitor is a uPA inhibitor. In another embodiment, the therapeutic agent further comprises a protease inhibitor selected from the group consisting of thiol protease inhibitors, acid protease inhibitors, and metalloproteinase inhibitors. In yet another embodiment, the protease inhibitors are co-administered with PAI-2, or a variant, derivative, or variant of a derivative of PAI-2. In still further embodiments, the PAI-2 or variant, derivative, or variant of a derivative of PAI-2 is administered in a range of 0.1-2000 xcexcg/cm2 of wound. In another embodiment, the PAI-2 or variant, derivative, or variant of a derivative of PAI-2 is administered at least once a day for at least five days.
In further embodiments, the derivative of PAI-2 is obtained by biochemical modification of PAI-2, where the modification is selected from the group consisting of chemical linking with polyethylene glycol, phosphate group attachment, sulfate group attachment, peptidase treatment, treatment with a sugar chain-modifying enzyme, and treatment with a sugar attachment enzyme. In still other embodiments, a variant of PAI-2 is obtained by deletion or addition of amino acid residues from the amino terminal end of PAI-2. The variant may be obtained by deletion or addition of amino acid residues from the carboxy terminal end of PAI-2.
In accordance with another aspect of the invention there has been provided a pharmaceutical composition comprising PAI-2 or a PAI-2 derivative, variant, or variant of a derivative, in a gel containing a detergent. In one embodiment the detergent is Tween-80, and the gel is a cellulose gel.
In accordance with another aspect of the invention there has been provided a pharmaceutical composition comprising PAI-2 and at least one other serine protease inhibitor. The pharmaceutical composition may further comprise a protease inhibitor selected from the group consisting of thiol protease inhibitors, acid protease inhibitors, and metalloproteinase inhibitors. In another embodiment, the composition is in the form of a cellulose gel that comprises a detergent.
Other objects, features and advantages of the present invention will become apparent from the following detailed description. It should be understood, however, that the detailed description and the specific examples, while indicating particular embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.